Species: Actinemys marmorata
Encyclopedia of Puget Sound
Carapace is low and olive, dark brown, or blackish, usually with a pattern of dark radiating spots or lines on each scute; plastron is yellowish, often with dark blotching; top of head has black spots or network; adult males differ from adult females in having the vent posterior to the rear edge of the carapace (vs. at or anterior to the carapace edge), a paler throat, and a shell that usually is flatter and less heavily marked; young are brown or olive above, with yellow on the edge of the marginals and on the head, limbs, and tail; tail of young is nearly as long as the shell; adult carapace length usually 9-19 cm (Stebbins 1985).
Articles:
This article was originally published by the Washington Department of Fish and Wildlife as part of its annual report Threatened and Endangered Wildlife in Washington.

Classification
Chelonia
Cryptodeira
Emydidae
Actinemys
NatureServe
Classification
Ecology and Life History
Carapace is low and olive, dark brown, or blackish, usually with a pattern of dark radiating spots or lines on each scute; plastron is yellowish, often with dark blotching; top of head has black spots or network; adult males differ from adult females in having the vent posterior to the rear edge of the carapace (vs. at or anterior to the carapace edge), a paler throat, and a shell that usually is flatter and less heavily marked; young are brown or olive above, with yellow on the edge of the marginals and on the head, limbs, and tail; tail of young is nearly as long as the shell; adult carapace length usually 9-19 cm (Stebbins 1985).